Method of processing asbestos ore



April 24, 1956 F. o. REEDY 2,743,059

METHOD OF PROCESSING ASBESTOS ORE Filed June 14, 1954 4 Sheets-Sheet l t &

a q, INVENTOR.

f 0. .R afdy BY W ' HTTQRNEY.

April 24, 1956 F REEDY 2,743,059

METHOD OF PROCESSING ASBESTOS ORE Filed June 14, 1954 4 Sheets-Sheet 2 *1 INVENTOR.

[ 171! Reedy BY w z/W April 24, 1956 F. o. REEDY 2,743,059

METHOD OF PROCESSING ASBESTOS ORE Filed June 14, 1954 4 Sheets-Sheet 3 INVENTOR.

Ii ii [1 0. Reedy Ap il 1956 F. o. REEDY 2,743,059

METHOD OF PROCESSING ASBESTOS ORE Filed June 14, 1954 4 Sheets-Sheet 4 INVENTOR. f 0 ji, @6(@ WWW IYTYWRNEK METHOD OF PROCESSING ASBESTOSQRE lined:flrkeedypDanville, Pat, assignor to Kennedy-Van ;SauntMg.; &-Engr. Corporation, New- York, N. Y., a. corporationof Delaware I I Application- June 14, 1954, Serial No. 436,498

3. Claims. (c1. 241-4 This invention relates to processing asbestos ore to removeithe'asbestos fiber from the asbestos ore.

]It 'is' th'e' object of the invention to. remove all possible asbestos fiberfrom the asbestos ore with the medium expen-se and" in a medium amount of time without unduly damaging the asbestos fiber.

The embodiment of the invention comprises successive steps of crushing] the asbestos ore, in a closed circuit in-: eluding a vibrating-screening zone, to any desirable size to produ'cefgreatest recovery of longest fiber, passing said crushedasbestos ores through an air-swept tumbling zone to" remove asbestos fiber from the crushed asbestos ore, removing the asbestos fiber from the tumbling zone in airstreamof said zone. and passing said asbestos fiber through: successive separating or cl'assifyingzones to a place of temporary storage, and simultaneously removing the tumbled-crushed asbestos ore from the tumbling zone toaanother, place of. temporary storage, removingsaid tumbled-crushed asbestos ore irom its place of temporany storage to a second, closed circuit of crushing said asbestos ore to, a smaller size to remove fiber without destmlction and depositingsaid smaller size asbestos ore in a .pl'aceof temporary storage, said, second closed circuit ofi crushing including a vibrating-screening zone, removing primary s't'orageto successive shalring screening zones to remove the. asbestos fiber from the smaller size asbestos.

ore and' transport said asbestos fiber through separating andcleaning zones to places of temporary storage and simultaneously returning. the smaller size asbestos ore from the last shaking-screening zone to a. place of temporary s.torage,, removing the asbestos. fiber from the last p1aQes .of-' temporary storage. to the successive shakingscreeningzones to remove asbestosore from, the asbestos. fiber and-returning the fiber to places of temporary storage through the separatingI andcleaning zones and simultaneously returning the separated asbestos ore to the place temporary storage, removing the separated asbestos orefromthe place of temporary storage. to an air-swept pulverizing, zone. to. further remove asbestos fiber from said asbestos. ore and pass said asbestos, fiber through successive separating or classifying; zones to. a place of temporary storage and simultaneously recirculating the ashestosnore through. the air-swept'pulverizingzone, removing the asbestos fiber from the placev of temporary storage tothe successive shaking and screening. zones to removeasbestos ore from said fiber and passing the as: bestos-fiber' through the separating and cleaning zones-to the places'of temporary fiber storage and simultaneously transportingthe asbestos ore-to the place. of temporary orestorage, removing the asbestos ore from the place of temporary orestorage-to the air-swept pulverizing zone tmremoveall remainingasbestos fiber and'passing said removed asbestos fiber through the successive separatingand cleaning zonesto the places of temporary storage andLsi-multaneonsly dumpingv the asbestos ore from the air-sweptrpulverizing zone, removing the asbestos fiber from the places of temporary storage to a gradingfzone to remove the short asbestos fiber and storesai d'short fiber, either passing the long asbestos fiber from the grad ing zone through a fiberizing zone. and the; separating zone to the first place of temporary storage or passing thelong, asbestos fiber from the grading zone through a fiber opening zone, the successive shakingasorjeening: zones and. returning to the grading zone andthen to the fiberizing zone to the .place ofstorage through the. sepae rating zone, removing the long asbestos fiber from. the place of temporary storage to a second grading zone to remove. all long fiber, and finally storing the fiber. In the drawings accompanying and forming a parrot this application: a Figure lis an elevational view ofthe appara'tustfor carrying out the present method of processing asbestos ore; Figure 2 is a top plan view offthe' apparatus looking from the line 22 of Figure 1' in the direction of the arrows; t .j Figure 3 is an elevational view'of the apparatus lookf ing from the line 3--3' of Figure l' in the direction of the arrows; and p I Figure 4 is a top plan view of the apparatus looking from the line 44 of Figure 1 in the direction oithe To carry out the firststep of' the present method. of processing asbestos ore, as shown in.Figures l, 2and 3,, the ore is fed into a closed circuit crushing zone re'pre; sented by a gyratory crusher 5 wherein the ore is crushed, to a size of one and one-quarter inches. The crushed'v ore is removed fromthe crusherS by a bucket type eleva-.

tor 6 to a three-decked vibrating screen 7' whereby the ore rejected by the top deck is returned by a conduit} to the crusher 5 and ore. rejected" by the two lower decks is conveyed by a conduit 9 to a temporary crushedore storage bin 10.

The second step of the method of processing asbestos ore, as shown in Figures 1 and 2 is to pass the crushed ore of one and one-quarter inches size through an air swept tumbling zone. Said tumbling zone is represented in the drawings by an Air-Swept rotary tube mill" 1'1 which does not contain any pulverizing media, such as. steel balls. Said crushed ore is transported from/the bin 10 to the mill 11 by a reversible belt conveyor 12' traveling below the discharge outlet'13 andtraveling in the present instance toward and discharging, the crushed ore into a conduit 14 to deliver tliecrushed ore to the lower end of a bucket type elevator-.15. *Saidelevator 15 hits and discharges the crushed ore into a conduit 16 delivering the crushed ore intoasurge bin 17 discharging; the crushed ore to a disk feeder'18'." The disk feeder ls'feeds the crushed ore to an air slide 19 delivering the crushed ore to the charging end. of the mill 11'. The: flow of the air supplied to the mill" 11 is heated if the crushedore is moist. The asbestos fiber is separated from the crushed asbestos ore by-the tumbling action of the mill 11. The separated. asbestos fiber is carried out of the discharge end of the mill 11 by the air stream. through a conduit 20 into a radia-l fiow' classifier .21. The fiber is discharged from the classifierll through a conduif 22 to a cyclone 23 and the ore and dust particles suspended in the air stream are discharged from the classifier21 through a conduit 24 to acyclone 25'. The asbestos fiber separated in the cyclone 25"is,discharged' into acondnit 26' connectedto the conduit'22' to convey the fi-be'r tothe cyclone 23. The air outlet of the cyclone 25' is connected to the inlet of pneumatiomeans 27 discharging through a conduit 28 into a sly dust filter 29. Dust and ore particles are-removed from the asbestos fiber in the" cyclone 23 and the asbestos fiber is dischargedfr'om? the cyclone 23 into a temporary fiber storage bin30. The

asbestos'ore is simultaneously discharged from the mill l'finto'a' conveyor to be conveyed to a bucket type elevator 31 discharging the asbestos ore into a conduit 32 declining to the conduit 14 to transfer the asbestos ore .to, the elevator 15 to deposit the asbestos ore into, a temporary ore sto'rage'bin 33 through a conduit 34.

The third step in processing the asbestos ore, as shown in Figures 1, 2 and 3, is to further reduce the size of the asbestos ore which has been tumbled in the mill 11 and deposited in the storage bin 33. This is accomplished in thejstrueture shown in the drawings by passing said asbe 'stos ore'through a second closed circuit crushing zone, as follows: The asbestos ore is charged from the stor-, age bin 33 onto the conveyer 12 operated to travel and discharge said asbestos ore through a chute 35 into 'a second gyratory cru'sher'36 discharging the crushed asbestos ore into the elevator 6 to be transported to the three-decked vibrating screen 7. The asbestos ore larger than 'the desired size is discharged from the screen 7 to 'the' conduit 8 for returning said ore to the crusher 36 anddepositcd inthe storage bin is approximately onequarter inch.

The fourth step in the present process is to remove the asbestos fiber from the one-quarter inch size asbestos ore in the storage bin 10. This is accomplished in the apparatus shown in the drawings by discharging said ore' from the storage bin 10 onto the conveyer 12 operated to travel toward the elevator 6, as shown in Figure 1, to feed the ore to a chute 37 for transferring the asbestos ore to the elevator 6. The ore is lifited by the elevator 6 to be discharged through a conduit 38 into the uppermost shaker screen of three-stepped shaker screens 39, 40 and 41. The asbestos fiber separated from the crushed asbestos ore by screen 39 is drawn from said screen through a conduit 42 into a cyclone 43 to separate dust and fine particles from the fiber. The clean fiber is discharged from the cyclone 43 into a temporary fiber storage bin 44. The asbestos ore is discharged from the screen 39 to the screen 40 to further separate the fiber from the ore and said separated fiber is drawn from the screen 40 through a conduit 45 into a cyclone 46 to separate dust and fine particles from said fiber and the clean fiber is discharged from the cyclone 46 into a temporary fiber storage bin 47. The ore is discharged from the screen 40 to the screen 41 to still further separate the fiber from the ore. The separated fiber is drawn from the screen 41 through a conduit 48 to a cyclone 49 for the removal of dust and fine particles from said fiber. The clean fiber is discharged from the cyclone 49 to a temporary fiber storage bin 50. An, air stream is caused to flow through the cyclones 23, 43, 46 and 49 for drawing the fiber into said cyclones by a suction fan 50', Figures 3 and 4, having the inlet connected by a conduit 51 to the air and dust outlets of the cyclones and the outlet of the fan is connected through a conduit 52 to a sly dust filter 53 having an exhaust 54. Destructive particles are removed from the air being drawn into the fan 50 from the eyclones 23, 43, 46, 49 to prevent damage to the fan by a conduit 55 connected to the conduit 51 in adva'nce of the connection of theconduit 51 tothe fan. 50'- The fifth step in processing the asbestos ore is to pass. the fibers in the temporary storage bins 30, 44, ,47 and 50 through a shaker-screenzone represented by the screens 39, 40 and 41 to remove the asbestos ore from said asbestos fiber. This is accomplished by discharging the asbestos fiber from the bins 30, 44, 47 and 50 intoa conveyer having two sets of blades pitched in opposite directions, one set of blades 62 extending from one end of the conveyer to the center of the conveyer to convey the fiber from said end to the center of the conveyer and the other set of blades 63 extending from the opposite end of the conveyer to the center of the conveyer to convey the fiber from said end to the' center of the conveyer, as indicated in broken lines in Figure 1. The fiber is dis-. charged from the center of the conveyer 62, 63 through a conduit 64 extending to the shaker screen 39. The operations of the shaker screens 39, 40 and 41 and the disposals of the asbestos fiber and ore are the same as in the fourth step except that the fiber discharged from the cyclones 43, 46 and 49 is deposited in temporary fiber bins 65, 66 and 67, respectively. The discharge of the fiber from the cyclones 23,. 43, 46 and 49 is controlled by a rotary valve in the fiber discharge outlet of each byclone, as indicated at 68 in Figures 1 and 3, whereby the fiber is discharged into either of two discharge spouts 69, 70, each spout leading to an adjoining storage bin.

The sixth step in processing the asbestos ore is to pass the ore in the temporary ore storage bin 61 through a pulverizing zone illustrated in the drawings as comprising an Air-Swept ball tube mill 71 which is similar to the Air-Swept mill 11 except that the mill 71 is provided with attritive or grinding elements, such as steel balls. The ore is discharged from the bin 61 onto the conveyor 12 operated to travel toward the elevator 15 to discharge the ore into the conduit 14 and thence to the elevator 15 to be elevated to the conduit 16 for delivery to the surge bin 17, the disk feeder 18 and a conduit 71 to the charging end of the mill 71. The separated asbestos fiber is removed from the mill by the air stream through a conduit 72 to a radial flow classifier 73. The asbestos fiber is discharged from the radial flow classifier through a conduit 74 to the cyclone 23 and temporary fiber storage bin 30. The air, dust and small particles are discharged from the classifier 73 through a conduit 75 to the cyclone 25. The fiber in the cyclone 25 is discharged through the conduit 22 to be delivered to the temporary fiber storage bin 30 through the classifier 23. The ore is discharged from the mill 71 'into a conduit 76 leading to the elevator 31. The ore is discharged from the elevator 31 into a conduit 77 leading to the charging end of the mill 71 whereby the ore is pulverized in a closed circuit until the desired amount of fiber is removed therefrom.

The seventh step in processing the asbestos ore is to pass the fiber which has been the product of the 'pulverizing zone through the shaker-screen zone by discharging said fiber from the bin 30 to the conveyer portion 62 and the screen 39 where the fiber and ore are processed in the same manner as in the fourth step;

Should it be found that the ore discharged fromthe screen 41 and deposited in the bin 61 in the seventh step contains sufiicient fiber, said ore is discharged from the bin 61 onto the conveyer 12 for transference by the ele-' vator 15, the conduit 16, surge bin 17, disk feeder 18 and conduit 71 to the mill 71 to pulverize said ore. The. products of said pulverizing zone are treated in the .same. manner as in the sixth and seventh steps.

The eighth step in processing asbestos ore consists of, grading the fiber in the bins 65, 66 and 67 by discharg ing said fiber from the bins 65, 66, 67 into the conveyer 62, 63 and from the conveyer 62, 63 into a conduit 78 leading to a grader 79 for grading the fiber into long.

' and short fiber and depositing the short fiber in finished.

fiber storage bins 80.- The long fiber is discharged from the, grader 79 through a conduit 81 -to a fiberizer. 82 ,and'

the fiber is discharged-from, the fiberizer- 82 through a conduit 83 to the cyclone 23 and the storage-bin-30.

' If the'fiber discharged from the grader .79'is,.extra.:

long, said fiber .is first discharged from the grader. 79

through a conduit 84 to a fiber opener 85 and the fiber is discharged from the fiber opener 85 to the cyclone 23, thejbin 30 and the shaker-screens 39, 40, 41 with the products of said screenings going to the bins 65, 66, 67 in accordance with the seventh step. The fiber in the bins 65, 66, 67 will be then conveyed to the grader 79 and the fiberizer 82 in accordance with the eighth step.

The ninth step in processing asbestos ore consists of grading the fiber which has been passed through the fiberizer 82 by discharging the fiber from the bin 30 into the conveyer portion 62 to be transferred through the conduit 78 to a second grader 86 discharging long fiber to a finished fiber bin 87 and medium and short fiber to separate bins 88 for blending as is necessary.

If necessary all fiber may be regraded by passing directly to the grader 86 by manual operation.

As shown in the drawings, the crushers 5 and 36, mills 11 and 71, the finished fiber storage bins 80, 87, 88, the fiberizer 82 and the'fiber opener 85 are mounted on the ground floor 89 of a housing structure 90 having a second floor 91 supporting the sly dust filter 29, the fan 27, the cyclone 25, the classifiers 21 and 73, the surge bin 17, the disk feeder 18, the ore storage bins 10, 33, 61, and the graders 79, 86. A third floor 92 supports shakerscreens 39, 40, 41, and the cyclone collector 56. A fourth floor 93 supports the fiber bins 30, 44, 47, 50, 65, 66, 67, the fan 50 and the sly dust filter 53. A fifth floor 94 supports the cyclones 23, 43, 46, 49. All the floors are indicated in Figure 3. The elevators 6 and pass through all the floors, and the elevator 31 passes through the second and third floors.

Having thus described my invention, I claim:

1. The method of processing asbestos ore, comprising crushing the ore in a closed circuit to a desired size,

tumbling the crushed asbestos ore of desired size in an air stream to remove asbestos fiber from said crushed asbestos ore, transporting the asbestos fiber from the tumbling zone by the air stream through a separating zone to separate the fiber from the ore and dust particles suspended in the air stream, passing the separated asbestos fiber through a screening zone to remove ore adhering to the fiber, transporting the fiber from the screening zone to a second fiber separating zone, transporting the asbestos fiber from the second fiber separatzone to a grading zone to separate the long and short fiber and deposit the short fiber in storage.

2. The method of processing asbestos ore as claimed in claim 1, transporting the long fiber from the grading zone to a fiberizing zone, transporting fiberized fiber to a second grading zone to grade and store all fiber.

3. The method of processing asbestos ore as claimed in claim 1, transporting the long fiber from the grading zone to a fiber opening zone, transporting the opened fiber to a screening zone and returning the screened fiber to the grading zone.

References Cited in the file of this patent UNITED STATES PATENTS 253,742 Meech Feb. 14, 1882 1,317,852 Ashenhurst Oct. 7, 1919 1,484,208 Davis Feb. 19, 1924 1,708,195 Stebbins Apr. 9, 1929 2,280,903 Ellison Apr. 28, 1942 OTHER REFERENCES Bowles: Information Circular 6869, December 1935, Dept. of the Interior, Bureau of Mines, Asbestos-Milling, Marketing and Fabrication, pp. 4, 5 and 6. (Copy in Division 55.) 

1. THE METHOD OF PRECESSING ASBESTOS ORE, COMPRISING CRUSHING THE ORE IN A CLOSED CIRCUIT TO A DESIRED SIZE, TUMBLING THE CRUSHED ASBESTOS ORE OF DESIRED SIZE IN AN AIR STREAM TO REMOVE ASBESTOS FIBER FROM SAID CRUSHED ASBESTOS ORE, TRANSPORTING THE ASBESTOS FIBER FROM THE TUMBLING ZONE BY THE AIR STREAM THROUGH A SEPARATING ZONE TO SEPARATE THE FIBER FROM THE ORE AND DUST PARTICLES SUSPENDED IN THE AIR STREAM, PASSING THE SEPARATED ASBESTOS FIBER THROUGH A SCREENING ZONE TO REMOVE ORE ADHERING TO THE FIBER, TRANSPORTING THE FIBER FROM THE SCREENING ZONE TO A SECOND FIBER SEPARATING ZONE, TRANSPORTING THE ASBESTOS FIBER FROM THE SECOND FIBER SEPARATING ZONE TO A GRADING ZONE TO SEPARATE THE LONG AND SHORT FIBER AND DEPOSIT THE SHORT FIBER IN STORAGE. 